Koodihommia

React native 0.64 by default has "inline requires"  enabled. We can now easily squeeze some milliseconds out of the app startup time. Here are a couple of examples of how to do it with React Navigation . If some navigation paths are behind feature flags, you can import them conditionally at the navigator level, skipping potentially unused code to be loaded on startup while preventing users' access to unreleased features. You can also create lazy loading screens that will require the actual implementation only when it has received a navigation event.

We used a Google "distroless" image as the base image on a go application deployment in a project a while ago. I never looked into what distroless really means, but I had a guess. I'm also curious to look under the hood of a docker image if they really are just merged archives. Recently there was a "Docker without docker" blog post in Hacker news about how simple docker (or rather, OCI) image format is. Spoiler: an image is tar archives on top of tar archives. The post has also a detailed explanation of how to pull images from a container registry. I shamelessly took the image pull script they shared and modified it a bit to pull the static distroless image from the Google container registry. The image is only one layer, and here is how it looks like after I extracted it and removed all the root level empty directories with all directories with at least one file expanded. It looks pretty empty to me, and I suppose that's th...

I learned from my brilliant colleagues a nice trick that left me once again wondering why on earth I discover these things only now. It's funny to run into something literally everyone else knows, and somehow, I miss. Say you have a file that you want to download on some trusted server. You may have a version of the file downloaded, but it may be somehow corrupted or partially downloaded. You could verify the file integrity by comparing the local and remote file hashes, and that is indeed a proper way to do it.  If you trust the remote, you can use plain old HTTPS to get the headers only with a HEAD request and get the content length. Just compare the result to local, and there you have it, a naive yet adequate method to check if you need to redownload a file. Note that this does not validate that the file contents are equal. 

Of all the horrific code I have written, by far, the most harmful and destructive have involved too early abstraction. Everyone knows the issues stemming from the wrong abstraction. Even copy-paste code would have been a better choice than creating some seemingly fancy, say, adapter pattern implementation. To be honest, I think copy-paste has a worse reputation than it should. A given project might have started with best practices, module structure, libraries of a prior project/16k star primer. That can be good! Some best practices naturally transcend projects. We should bring in the lessons learned but the timing matters. Upon a closer look, the project might indeed have agreeable abstractions. Still, those could be hollow and bring only extra LOCs and solve the issues faced in the previous projects, which have never occurred in the current one. Upon recently starting two soon-to-be large projects, I learned to leave some wisdom from previous lives behind. While deep in the coding zen...

A common thing I see in an enterprise system is that when an end-user does some action, say add a user, the underlying web of subsystems adds the user to multiple databases in separate transactions. Each of these transactions may happen in varying order and, even worse, can fail, leaving the system in an inconsistent state. A better way could be to write the user data to some main database and then other subsystems like search indexes, pull/push the data to other interested parties, thus eliminating the need for multiple end-user originating boundary transactions. That's the theory part; how about a technical solution. The idea of this post came from the koodia pinnan alla podcast about event-driven systems and CDC . One of the discussion topics in the show is emitting events from Postgres transaction logs.  I built an utterly simple change emitter and reader using Postgres with the wal2json transaction decoding plugin and a custom go event parser. I'll stick to the boring ...

Virtually all of the audio plugin development is done in low-level languages like C++ to keep the illusion of real-time as close to being true as possible. Recently though, ROLI released a new programming language for audio processing. It's called  SOUL , a less convoluted way of designing audio processing software. I took a look at it and in no time, created this simple detuned sinewave synth. Sure, it is pretty much based on the examples but it took only a couple of hours to implement. If I would have done this in C++, a week would not have been enough. SOUL provides abstractions for inputs and outputs, lots of ready-made functions for waveforms, phases, and time-to-frequency domain conversions. It's pretty new though and examples, editor support, and proper documentation is still lacking. I plan to keep an eye on the development and will return with some more demanding audio processing later on.  You can try the example on the browser by copy-pasting it to the browser play...

Back in the day, everyone was using Winamp. It is a music player with the user interface of a mixing console. The bloody thing had an equalizer on the front page! As an amateur music producer, I know that EQ is a powerful tool but making changes that sound good is difficult, to say the least. Mixing engineers spend considerable effort with the artist to balance the frequency ranges to arrive at the desired musical outcome. I bet the 15-year-old me butchered a lot of songs with the thing. Now we are using Spotify, a player with basically a search bar and a play button. I ran into something called Ousterhout's Law on the  Operating Systems: Three Easy Pieces book . Here is a quote from the book TIP: AVOID VOO-DOO CONSTANTS (OUSTERHOUT’S LAW) Avoiding voo-doo constants is a good idea whenever possible. Unfortunately, as in the example above, it is often difficult. One could try to make the system learn a good value, but that too is not straightforward. The frequent result: a configura...